I have a 2015 MacNook Pro and I love it, but around Sierra OSX it became unusably slow. So I decided to bet on Ubuntu. There are a few quirks with this like the webcam won't work without compiling some drivers, the wifi neither.
I've learned to deal with these quirks, I even accept every ubuntu base update I lose my wifi driver and its a pain to get it back without internet. Hot tip if you face this issue share your network over bluetooth from an android.
So I decided to upgrade to 21.04 why not? I've upgraded the distro versions before no problemo.
It worked, no bugs, no weirdness.. hooray.
5 days later... I turn on my machine and nothing... literally nothing just a black screen. So I start googling, a few posts are saying its just a display issue use a few keys to fix it. It made sense as 21.04 was supposed to use Wayland instead of X11. No luck.
Now I'm trying to get into safe mode to get a cli and try bootrepair, nadda. I burn a usb and manage to boot bootrepair, still no fix.
This is days of hair pulling debugging. I finally find one obscure post, apparently this version of Ubuntu just writes over your efi launch settings... I was at a loss of what to do. I tried my luck and installed reFind a boot loader, boom fixed.